HVLP Spray Guns

The human mind often exhibits a strange inability to make connections between different physical phenomena that are common in our everyday world. For example, the pull rings used to open sardine tins have existed since the Second World War, if not before, yet it took close to fifty years for anyone to realize that they could be fitted to other types of cans as well, leading to the “invention” of a convenience which could have existed several generations previously.

In the same way, although humans have known that liquids flow downhill for thousands of years, it took nearly a century for them to think of placing the paint cup above a spray gun’s nozzle, allowing gravity to help with the paint flow, rather than below it, even though the technology to create this arrangement is no more complex than that needed for the underslung cup.  However, the day of these devices had finally arrived, in the form of high-volume, low-pressure, or HVLP, spray guns.

These paint guns mount the paint cup above the nozzle, where gravity can help feed the paint into the stream of pressurized air. Some siphoning or suction does still occur, but it is helped greatly by the natural downward flow of the paint. This allows the nozzle pressure to be low enough to cut back immensely on overspray. A sizeable amount of overspray still occurs, even with the relatively limp pressure and typical spraying distance of only four inches to the car’s surface, but it is far less than with a regular siphon feed gun.

The air enters the gun at 60 psi or so, but leaves it at only 5 to 10 psi, meaning that it ricochets off the sheet metal far less than with 35 or 55 psi paint from an older style of gun. A stronger compressor is needed to maintain the pressure, since not only is slightly higher pressure needed to work the HVLP gun, but there is also a need for steady pressure. The compressor cannot start and stop as it can with an older model – it must run more or less constantly to keep up the correct volume.

The higher cost of this larger compressor is quickly offset by the savings on $300 per gallon paint that is not lost to the atmosphere, however. If you can afford the larger initial outlay for the HVLP setup, then you will soon accumulate enough savings to prompt you to congratulate yourself on your thrifty decision. You can expect only 30% to 38% of your paint to be wasted as overspray, which means that you will lose 1 gallon out of every three gallons you spray – rather than losing three gallons out of every four you spray. 

HVLP guns are very easy to use, providing good spray and good handling thanks to their lightness. This lightness makes them easier to hold at the correct angle for long periods of time, and thus lessens the chance of errors in thickness when applying a coating of paint. Their use may be summed up as needing a larger initial outlay than siphon feed guns, but being far more efficient, cost-effective in terms of paint, and clean from an environment standpoint.